Exp Neurobiol.  2019 Jun;28(3):320-328. 10.5607/en.2019.28.3.320.

Basal Forebrain Cholinergic-induced Activation of Cholecystokinin Inhibitory Neurons in the Basolateral Amygdala

• Lee S
• Kim JH

• KMID: 2451068
• DOI: http://doi.org/10.5607/en.2019.28.3.320

Abstract

The basolateral amygdala (BLA) receives dense projections from cholinergic neurons of the basal forebrain. Acetylcholine can contributes to amygdala-dependent behaviors: formation and extinction of fear memory and appetitive instrumental learning. However, the cholinergic mechanism at the circuit level has not been defined yet. We demonstrated that cholinergic-induced di-synaptic inhibition of BLA pyramidal neurons exhibits a retrograde form of short-term synaptic inhibition, depolarization-induced suppression of inhibition (DSI). Activation of nicotinic receptors was sufficient to evoke action potentials in cholecystokinin (CCK)-positive inhibitory neurons, which strongly inhibit pyramidal neurons through their perisomatic synapses. Our cell type-specific monosynaptic retrograde tracing also revealed that CCK neurons are innervated by basal forebrain cholinergic neurons. Therefore, our data indicated that CCK inhibitory neurons mediate the cholinergic-induced di-synaptic inhibition of BLA pyramidal neurons.

Keyword

Cholecystokinin; Acetylcholine; Di-synaptic inhibition; Basolateral amygdala; Iontophoresis; Retrograde tracing

MeSH Terms

Acetylcholine
Action Potentials
Basal Forebrain*
Basolateral Nuclear Complex*
Cholecystokinin*
Cholinergic Neurons
Conditioning, Operant
Iontophoresis
Memory
Neurons*
Pyramidal Cells
Receptors, Nicotinic
Synapses
Acetylcholine
Cholecystokinin
Receptors, Nicotinic